Why such a delay?

We all have images of 9/11 burned into our brains. Some of us more than others, depending on our proximity to the World Trade Center on the morning of Sept. 11, 2001.

Even all those who watched the whole thing unfold on TV from miles away will retain vivid mental pictures of that day to the end of their days.

But most of what we remember is from a ground-level perspective.

Maybe that’s why the aerial photos of the devastation in downtown Manhattan are so stunning. They showed the totality of a scene of horror far below the camera’s lens.

The photos, taken by a New York Police Department detective from a police helicopter, were made public last week.

The images are “absolutely core to understanding the visual phenomena of what was happening,” said Jan Ramirez of the National September 11 Memorial & Museum, adding they are “some of the most exceptional images in the world, I think, of this event.”

Richard Zimbler, president of the WTC Survivors Network, said the photographs, which number in the thousands, “are an important part of the historical record.”

We agree. The question we have is why it took until February 2010 — eight years — for the world to get to see them.

The detective who took the shots, now retired, had shared them with friends and a few were published without authorization in a book.

The detective turned his film and digital images over the 9/11 Commission, which apparently transferred them to the National Institute of Standards and Technology, which also investigated the attacks.

But it took a Freedom of Information Act request by ABC News to get the photos released to the public.

Why? Other than the shock of seeing 9/11 from different angle, there’s nothing that would upset anyone any more than the widely broadcast images. And, after the event, there’s nothing in those photographs that would threaten national security or public safety.

As Mr. Zimbler said, they’re an important part of the historical record. So what was the government’s purpose in keeping them hidden away for all these years?

The best explanation seems to be that this is another example of the federal government’s fondness for secrecy, even when it’s not necessary in the least.